magnuson



April 12, 1938. H. o. MAGNUSON 2,114,111

SAFETY APPLIANCE FOR MOLDING MACHINES Filed Dc. 23, 193'? 2 Sheets-Sheet l 5? Q 39724 502 4 if Jaw z-Q L Czgfya:

April 12, 1938. H. o. MAGNUSON SAFETY APPLIANCE FOR MOLDING MACHINES Filed Dec. 23, 1957 2 Sheets-Sheet 2 Patented Apr. 12, 1938 UNITED STATES SAFETY APPL IANCE FOR MOLDING MACHINES Henry 0. Magnuson, Chicago, Ill., assignor to Champion Foundry and Machine Company, Chicago, 111., a corporation of Illinois Application December 2 8 Claims.

This invention relates to molding machines of the squeeze type, and has reference more particularly toa safety appliance designed to render the manipulation of such machines safe and forestall 5 any possible injury to the operative through carelessness or accident.

Molding machines of this type commonly em ploy a flask-supporting platform, a platen head that is pivoted either vertically or horizontally so as to swing sidewise or rearwardly between a working position directly overlying the platform and an idle position to-one side of the platen, and a pneumatic motor beneath the platform for raising the latter so as to compress and pack the sand in the flask around the pattern, the'compressicn being effected by the relative movement of the platform and head toward each other. A valve, usually opened by the right hand of the operative, is located in the fluid supply line to the motor. It has not infrequently happened that a careless operative, when opening the valve has allowed his other hand to get caught and crushed between the top board of the flask and the head.

Many of these machines also employ a device known as a jolter, operated by a rapidly reciprocating pneumatic motor, for imparting to the flask, during the loading thereof and before the final squeezing operation, a rapid vertical shaking 30 movement to evenly distribute the sand that has been shoveled into the flask; and following this shaking movement the operative adds a final shovelfull of sand and with his hands distributes and lightly packs it to complete the filling of the flask. The valve controlling the admission of compressed air to the jolter motor is usually opened by a handle that is pressed by the knee of the operative. When loading the flask and prior to operating the jolter the head is pushed to one side out of the path of movementof the platform and flask; but sometimes the operative fails to do this, and, while distributing and packing the final shovelfull of sand, he sometimes accidentally hits with his knee. and opens the jolter valve, with the result that his hands or wrists get caught and squeezed between the top "edge of the open flask and theplaten head;

The primary object of this invention has been to provide a'useful automatic accessory to a machine of this type that will render impossible either or both of the above described accidents. As will be seen from the following description, the first described accident is prevented by a means which requires both hands of the operative to be engaged 'in safe positions at the inception of and 3, 1937, Serial No. 181,257

during the squeezing operation; and the last described accident is prevented by a means that requires the head to be shifted entirely out of the path of the platform and flask before the motor of the jolter can be operated and to remain in such position until the flask is ready. for-the squeezing operation. v

An illustrative embodiment of this invention is shown in the accompanying drawings, in which- Fig. 1 is a perspective side view of a portable squeeze-type molding machine embodying my improvement. I Figs. 2, 3 and 4 are diagrammatic plan views, Fig. 2 illustrating the relative positions of the platform and platen head during the flaskjolting operation; Fig. 4 illustrating the relative posi tions of said parts during the flask squeezing op.- eration; and Fig. 3 illustrating intermediate positions of the platen head in and between which both the main operating valves ofthe squeeze motor and the jolt motor are rendered inoperative.

Fig. 5 is a sectional view of the auxiliary valve in the pipe line leading to-the squeeze motor. Fig. 6 is a similar viewof the awiliaryyalve in the pipeline leading tothe jolt motor; 1

First briefly describing the parts of thecmachine that are old and well known, 10 designates the heavy standard carrying the swinging platen head and its arm, and Il designates a castingsecured to the lower-front portion of the standard In asby bolts 12 and containing the squeezemotor, the cylinder and. annular plungerpfwhich are fragmentarily shown at l3,and M respectively, and the plunger 15 of the jolt motor which operates in a central bore of the plunger 14. The plunger 14 of .the squeeze motor carries on its upper end a platform H5 that supports the-flask. In the upper front portion of the standard I 5 is a vertical shaft ll, on which is journaled the elongated hub l8 of a forwardly projecting arm I9 carrying at its free end a'vertically'adjustable platen head 20. 1 k g H 1 2| designates the pipe line leading from a source of compressed airv or other motive fluid, and communicating with the line 2| is a branch 22 that supplies motive fluid to the squeeze motor and also a branch 23 that suppliesmotive fluid to the jolt motor. In the line 22 is a main selfclosing control valve indicated at 24 that-is opened by'the'operative by depressing a pivoted handle 25 conveniently accessible from the front of the machine; and in the line 23.is a main selfclosing control valve indicated at 26 that is so located astc be conveniently opened by the operator by pressing his knee against a depending valve handle 21.

I have herein shown a portable machine wherein the standard Ill and the casting II are supported on a rear wheel 28 and a pair of front wheels 29; but this portable feature has no relation to my present improvement, the latter being equally applicable to stationary machines.

Coming now to those features wherein my present improvement resides, in the branch line- 22 that serves the squeeze motor is inserted an auxiliary valve designated as an entirety by 30 and shown in enlarged section in Fig. 5. This valve is in itself" an old and well known type of valve and comprises a casting formed with opposed tapped branches 3| and 32 for insertion into the pipe line served thereby, a central chamber divided by a bridge 33 formed with a valve seat 34, and a plunger valve 35 slidable in a cylindrical guide 36 constituting a branch of the casting 30. The valve 35 has a gasket 31 cooperating with the seat 34, and in rear of the valve is a spring 38 footed on a nut 39 and forcing the valve 35 to its seat. To balance the air pressure on opposite sides of the valve when the latter is open, and to enable the air to assist the spring in holding the valve closed, the valve body is formed with a pair of opposed bleed ducts 40. On the face of the valve body 35 is formed a central socket 41 that receives the inner end of a stem 42 that is slidably mounted in and projects beyond a packed bearing 43.

On the upper end of the hub l8 of the arm 19 is a laterally projecting lug 44 shown in top plan view in Figs. 2, 3 and 4, in which is mounted a striker screw 45 that lies in the same horizontal plane with the valve stem 42.

The spring 38 of the auxiliary valve 30 is of suflicient strength to overcome the inertia of the arm l9 and its head 20.

Briefly describing the function and operation of the auxiliary valve 30, when the operative is ready to squeeze the flask, with his left hand he grasps a handle 46 on the free end of the arm I9 and swings the latter from the off position shown in Fig. 2 to the working position shown in Fig. 4. During the latter part of this swing, the screw 45 strikes the projecting end of the valve stem 42 and forces the latter inwardly, unseating the valve and admitting fluid pressure to the portion of the line. 22 beyond the valve. He then with his right hand depresses the main valve handle 25 and holds the latter depressed until the squeezing operation is completed. During this squeezing operation it is necessary for him to hold the head 20 in its working position (Fig. 4) since, if he lets go, the valve spring 38 acting through the stem 42 will push the head 20 to the inoperative position shown in Fig. 3. Thus, at the inception of and during the flask squeezing operation botli hands of the operative are occupied in safe positions where neither hand can become accidentally injured.

In the line 23 that serves the flask jolting motor I also preferably interpose an auxiliary valve designated as an entirety by 30. As seen by a comparison of Figs. 5 and 6, the valves 30 and 30 are identical except that the spring 38' of the valve 30' is weaker than the spring 38 of the valve 30 and, in fact, is of insuflicient strength to overcome the inertia of the head 20 and its arm l9. On the arm I9 is a lug 4! that extends into the horizontal plane of the valve stem 42' of the valve 30'. The valve 30 is normally held closed by both its spring 38 and the differential air pressure behind it, so that if the operative loads the flask on the platform 16 while the head 20 is at or between the positions shown in Fig. 3, and accidentally strikes the main valve handle 21 with his knee, he cannot be injured during the jolting operation, since the motive fluid cannot reach the jolt motor until the head 20 has been swung entirely clear of the vertical path of travel of the platform and flask, as shown in Fig. 2, which opens and holds open the auxiliary valve 30. Even if the head be swung to the position shown in Fig. 3, its arm does not open the auxiliary valve 30', so that with the head 20 in or anywhere between the positions shown in Fig. 3, the machine is inoperative either for jolting or squeezing the flask. When squeezing, the hands of the operative cannot be injured because they are both in safe positions. When jolting, they cannot be injured by accidental opening of the main jolt valve because the arm and head are wholly to one side of the path of travel of the platform and flask.

Manifestly, either of the safety features represented by the auxiliary valves 30 and 30' may be employed without the other; but the maximum safety of the machine is obtained by the use of both.

The structural details of the auxiliary safety valves and their operating devices may, of course, be varied from those shown and described without departing from the principle of the invention or sacrificing any of its advantages. Hence, I reserve all such variations and modifications as fall within the spirit and purview of the claims.

I claim:

1. The combination with a molding machine of the squeeze type having a flask supporting platform, a fluid pressure motor for raising said platform, a platen head movable between positions above and to one side of said platform, a motive fluid supply line for said motor, and a manually operable valve in said line, of a selfclosing auxiliary valve in said line, and means whereby said auxiliary valve is opened when said head is moved to and held in working position above said platform,

2. The combination with a molding machine of the squeeze type having a flask supporting platform, a fluid pressure motor for raising said platform, a platen head movable between positions above and to one side of said platform, a motive fluid supply line for said motor, and a manually operable valve in said line, of a normally closed auxiliary valve in said line, means whereby said auxiliary valve is opened when said head is moved to and held in Working position above said platform, and means automatically moving said head out of working position and permiting said auxiliary valve to close if and when said head is not held'in working position.

3. The combination with a molding machine of the squeeze type having a flask supporting platform, a fluid pressure motor for raising said platform, a platen head movable between positions above and to one side of said platform, a motive fluid supply line for said motor, and a manually operable valve in said line, of a normally closed auxiliary valve in said line, said valve having a stem projecting exteriorly of said line, means whereby said auxiliary valve is opened through contact with said stem when said head is moved to and held in working position above said platform, and a spring closing said auxiliary valve and through said stem shifting said head out of 7 working position if and when said head is not held in working position.

4. The combination with a molding machine of the squeeze type having a flask supporting platform, a fluid pressure motor for raising said platform, an arm pivoted to swing laterally above said platform, a platen head on the free end of said arm, a motive fluid supply line for said motor, and a manually operable valve in said line, of a normally closed auxiliary valve in said line, said valve having a stem projecting exteriorly of said line, and a valve closing spring projecting said stem into the path of swing of said arm whereby the latter opens said valve when said head is moved into working position, said spring being strong enough to overcome the inertia of said arm and head thereby requiring the latter to be held in working position to maintain said auxiliary valve open during the squeezing operation.

5. The combination with a molding machine of the squeeze type having a flask supporting platform, a fluid pressure motor for jolting said platform, a platen head movable between positions above and wholly to one side of said platform, a motive fluid supply line for said motor, and a knee-operable valve in said line, of a self-closing auxiliary valve in said line, and means whereby said auxiliary valve is opened and held opened when said head is shifted to a position wholly to one side, and out of the path of travel, of said platform and flask.

6. The combination with a molding machine of the squeeze type having a flask supporting platform, a fluid pressure motor for jolting said platform, an arm pivoted to swing laterally above said platform, a platen head on the free end of said arm, a motive fluid supply line for said motor, and a knee-operable valve in said line, of a normally closed auxiliary valve in said line, said valve having a stem projecting exteriorly of said line, and a valve closing spring projecting said stem into the path of swing of said arm whereby the latter opens said valve when said head is swung entirely to one side of said platform, said spring being of insufiicient strength to overcome the inertia of said arm and head, whereby said valve remains open so long as its stem is contacted by said arm.

7. The combination with a molding machine of the squeeze type having a flask supporting platform, a fluid pressure motor for raising said platform, a second fluid pressure motor for jolting said platform, a platen head movable between positions above and to one side of said platform, motive fluid supply lines for both of said motors, a manually operable valve in the line serving said first-named motor, and a knee-operable valve in the line serving said second motor, of self-closing auxiliary valves in the respective lines, and means whereby the auxiliary valve in the line serving said first-named motor is opened when said head is moved to and held in working position above said platform, and whereby the auxiliary valve in the line serving said second motor is opened and held open when said head is shifted to a position wholly to one side, and out of the path of travel of, said platform and flask.

8. The combination with a molding machine of the squeeze type having a flask supporting platform, a fluid pressure motor for raising said platform, a second fluid pressure motor for jolting said platform, an arm pivoted to swing laterally above said platform, a platen head on the free end of said arm, motive fluid supply lines for both of said motors, a manually operable valve in the line serving said first-named motor, and a kneeoperable valve in the line serving said second motor, of a normally closed auxiliary valve in the line serving said first-named motor, said valve having a stem projecting exteriorly of said line, a valve closing spring projecting said stem into the path of swing of said arm whereby the latter opens said valve when said head is moved into working position, said spring being strong enough to overcome the inertia of said arm and head thereby requiring the latter to be held in working position to maintain said auxiliary valve open during the squeezing operation, and a normally closed auxiliary valve in the line serving said second motor, said last-named valve having a stem projecting exteriorly of said last-named line, and a valve closing spring projecting said last-named stem into the path of swing of said arm whereby the latter opens said last-named valve when said head is swung entirely to one side of said platform, said last-named spring being of insufiicient strength to overcome the inertia of said arm and head, whereby said lastnamed valve remains open so long as its stem is contacted by said arm.

HENRY O. MAGNUSON. 

